1. Field of the Disclosure
The disclosure relates in general to an energy harvesting heat engine and actuator, and more particularly, to an energy heat engine that can take advantage of a temperature difference between two adjacent regions, turning the temperature difference into mechanical movement, which, in turn, can be converted into other types of energy or power, such as, for example electrical power.
2. Background Art
As the world's demands for energy increases, new ways of harnessing energy are needed. Current Heat Engines such as the Rankine cycle require some sort of circulation pump for the working fluid, which adds expense and consumes energy lowering overall efficiency; or a displacer in the case of some Sterling Engine topologies. Also, the invention does not transfer the working fluid between two connected different temperature containers and/or heat exchangers as in the case of the Alpha Sterling Engine topology. The Heat Engine described in the application does not require a circulating pump for the working fluid, and unlike the Sterling Engine, which uses a single-phase working fluid; the working fluid can be a refrigerant in the saturated vapor-liquid state for low temperature operation.
The Heat Engine described does not use up any of the working fluid. The working fluid is completely contained and recycled. The Heat Engine described transfers energy from an external heat source into mechanical energy. The Heat Engine described is closed cycled, and does not use any form of internal combustion and therefore it does not emit any exhaust. The Heat Engine described can harness heat from conduction, convection, and/or radiation.
Potential applications include, but are not limited to, harnessing energy from a solar water heater, from waste heat, from a naturally occurring thermocline, artificially created thermocline, from a salt pond thermocline, heat from chemical reactions, heat from electrical power, geothermal sources, conventional fuels such as coal, natural gas, nuclear, direct solar radiation on the ground or in space.
Certain solutions have been proposed for such engines. One such solution is shown in U.S. Pat. App. Pub. No. 2012/0073298 published to Frem. Problematically, the construction shown suffers from several drawbacks, some of which are set forth herein. First, the manner in which the refrigerant is maintained leads to substantial liquid refrigerant within the cylinder over time, generally regardless of the angle and orientation of the crankshaft. Second, there is no control of heat transfer between the heat exchanger and the cylinders themselves, resulting in fluctuating temperatures and heat transfer from both the outside and the inside refrigerant to the cylinder. Third, the bending movements introduced by the piston movement transferred to rotational movement lead to losses and stresses within the piston, cylinder and connecting rod.